As seen in the attached drawing, my RV has two separate battery banks.
Battery bank #2 is connected to bus bars that feed the inverter with very hefty 4/0- 18 inch long cables.
The SCC and 120 chargers are also connected to the bus bars. The bus bars also feed a 6 AWG cable that runs to a position one and position 2, switch that feeds the RVs fuse panel.
A second battery bank is located 18 feet from the bus bars and is connected to the selector switch with 6 AWG cable
This setup allows battery bank 2 to act as a backup. Bank 2 is currently a lead acid battery, charged by the vehicle alternator.
I wish to replace it with one or more LFP batteries, and through the use of a selector switch that allows 1, 2, or both, charge them with the existing solar and shore power sources.
I do not have space to put all the batteries in one spot near the inverter.
This setup should charge both battery banks together (albeit more slowly).
The two concerns are that if one bank is run down and the other is not and I switch to both to charge there would be a rush of current from high to low?
Second is “if” I decided to turn on the inverter while the selector switch was turned to “both” (while charging or not) wouldn’t the inverter try to draw from bank 2, through the 6 AWG wire and potentially cause really bad things to happen when the nearest bank to the inverter ran low?
The simple answer it seems is to run much larger cable, but that is impractical both from a cost standpoint, and the fact that the flow from both sides runs through a fuse panel.
A selector switch inline on the charging cable to direct current to bank one, or bank two through a separate cable could work, but requires me to be there to switch over when one reaches full capacity.
Ideas?
Battery bank #2 is connected to bus bars that feed the inverter with very hefty 4/0- 18 inch long cables.
The SCC and 120 chargers are also connected to the bus bars. The bus bars also feed a 6 AWG cable that runs to a position one and position 2, switch that feeds the RVs fuse panel.
A second battery bank is located 18 feet from the bus bars and is connected to the selector switch with 6 AWG cable
This setup allows battery bank 2 to act as a backup. Bank 2 is currently a lead acid battery, charged by the vehicle alternator.
I wish to replace it with one or more LFP batteries, and through the use of a selector switch that allows 1, 2, or both, charge them with the existing solar and shore power sources.
I do not have space to put all the batteries in one spot near the inverter.
This setup should charge both battery banks together (albeit more slowly).
The two concerns are that if one bank is run down and the other is not and I switch to both to charge there would be a rush of current from high to low?
Second is “if” I decided to turn on the inverter while the selector switch was turned to “both” (while charging or not) wouldn’t the inverter try to draw from bank 2, through the 6 AWG wire and potentially cause really bad things to happen when the nearest bank to the inverter ran low?
The simple answer it seems is to run much larger cable, but that is impractical both from a cost standpoint, and the fact that the flow from both sides runs through a fuse panel.
A selector switch inline on the charging cable to direct current to bank one, or bank two through a separate cable could work, but requires me to be there to switch over when one reaches full capacity.
Ideas?